Safety razor and blade



Patented Aug. 22, 1944 SAFETY RAZOR AND BLADE Louis H. Young, West Newton, Mass-., assignor to Gillette Safety Razor Company, Boston, Mass, a corporation of Delaware.

Application November 2, 1943, Serial No. 508,686

8 Claims.

This invention consists in improvements in safety razor blades and includes within its scope a novel combination of safety razor and blade.

In order to insure the user of a safety razor that he may expect safe and satisfactory shaving performance it is of the utmost importanc that the amount of blade exposure be accurately determined and reliably maintained in use. By blade exposure is meant the distance by which th sharp edge of the blade projects beyond a plane tangent to the edges of the cap and guard. An edge exposure of .006" has been found by a long series of investigations to be the maximum. If this is increased even slightly the razor becomes dangerous and the user is likely to cut himself.

It will be apparent, therefore, that the most painstaking efforts of the manufacturer and highest degree of manufacturing skill are brought to naught if the blade is in any way distorted in being presented to or clamped in the safety razor. This danger of distortion is particularly imminent in handling blades of the more delicate mechanical design such as blades having a central slot intersecting and opening out through one end of the blade, Such blades, which may be termed open-end blades, being constructed of thin flexible steel are readily susceptible to distorting stress. For the reasons above explained if the side portions of such a blade are spread at their open end in the blade-clamping operation th razor becomes dangerous.

Open-end blades have the advantage that they may be conveniently used in a safety razor organization in which the cap and guard members are permanently connected and arranged for a limited amount of separation to permit the insertion of a blade between them. This obviates the necessity of taking the razor apart with the consequent liability of dropping or losing the parts. When used with such razors it has heretofore been considered necessary to provide pins or other projections on the razor spaced to fit reentrant recesses formed in the blade at that transverse edge thereof into whichvthe blade slot opens positively to engage the blade and prevent the spreading of its side portions while being clamped in flexed condition for shaving.

With these conditions in view, the principal object of the present invention is to provide an open-end blade of such shape and dimensions as to obviate the tendency to distortion when being engaged between the blade-clamping members of the razor and by so doing I have eliminated the necessity of providing the razor with pins or projections to hold the blade against spreading and have also done away with the substantial recesses in the ends of the bladeto receive such pins or projections.

In order to manufacture open-end blades under satisfactory conditions and to adapt the blades for the casual treatment they receive in ordinary use, there are certain characteristics of shape that must be retained. For example, it is most desirable to provide the blade with reentrant recesses in all corners to eliminate deflection of the blade by a damaged cap corner. Again, annealing of the blade strip by electrical resistance heating requires each blade to be provided with a longitudinal slot preferably as long as its sharpened edge, otherwise the annealing heat is likely to be conducted out into the end portions of the cutting edges and render them too soft for satisfactory shaving. The problem presented is complicated by these structural fea tures of the blade which must be preserved for the reasons indicated.

I have discovered that the difficulties above discussed may be avoided and important advantages secured by providing a flexible safety razor blade having a substantially rectangular body of thin sheet steel sharpened in its longitudinal edges, having a central longitudinal slot Which opens out through one of its end edges and being of such length that the said end edge lies within the confines of the blade-clampin members of the razor, being guarded thereby from a11 possible contact with the fingers of the userand so not in any way subjected to torsional strain when being engaged between the blade-clamping members of the razor. In a more specific embodiment of my invention that part of the blade having the slot opening in its transverse edge may be substantially shorter than the part of the blade having a solid or uninterrupted transverse edge.

The novel combination of safety razor and blade contemplated by my invention consists in blade-clamping members one of which is provided with a blade-locating projection of some kind, in combination with an open-end blade having a longitudinal slot cooperating with the blade-locating projection to hold the blade against transverse displacement when presented in a fiat position between the blade-clamping members, the slot extending at its closed end preferably to a point in line with the ends of the sharpened edges of the blade, While the open or intersected end edge of the blade is disposed flush with or within the adjacent end of the blade-clamping members Where it is shielded from contact by the fingers of the user.

These and other features of the invention wi11 be best understood and appreciated from the following description of a preferred embodiment thereof, selected for purposes of illustration and shown in the accompanying drawing, in which:

Fig. 1 is a plan View on an enlarged scale shoW- ing the blade of my invention as partially presented to the cap member of a safety razor;

Fig. 2 is a similar view showing the blade fully presented;

Fig. 3 is a view in cross-section of the razor with the blade clamped for shaving; and

Fig. 4 is a view of the razor and blade in elevation partly in longitudinal section on an enlarged scale, indicating also how the razor is usually held in the blade-clamping operation.

An important field of use for the blade of my invention is in double-edged blades of the Gillette type and in Figs. 1 and 2 the invention is shown in its application to such a blade. The body of the bladeis preferably formed of thin flexible sheet steel in the order of .004" to .006" in thickness. Its body It is substantially rectangular in outline being provided at each corner with a recess, herein shown as reentrant and as defining in the blade elongated end portions II and I2 bounded on all sides by un'sharpened edges. The corner recesses provide clearance spaces of sufficient area to prevent clamping pressure by the corners of the cap member of the razor. The opposite longitudinal edges I3 of the blade are sharpened throughout their full length. The blade is provided with a central longitudinal slot |4 terminating, in the embodiment of the invention herein shown, at one end in a transverse enlargement |5 having its end edge located substantially in line with and between the opposed ends of the sharpened cutting edges |3 of the blade. The slot I4 is provided with an intermediate circular enlargement 6 for the reception of the stem of the cap. At its other end the slot I4 is provided with a transverse enlargement I! and beyond this enlargement it intersects the end portion l2 and its unsharpened end edge, opening out through it as is characteristic of openend blades. The slot IA is herein shown as having other intermediate enlargements of various shapes and it will be understood that these are designed to fit blade-locating projections of corresponding outline in safety razors of difierent type from that herein shown.

The two longitudinal side portions of the blade set off by the longitudinal slot l4 are symmetrical in their relation but the blade herein shown is not symmetrical about its transverse axis. In the embodiment herein shown that portion of the blade which includes the solid end portion H is longer than the corresponding portion of the blade including the intersected end portion l2. In Fig. 2 the transverse axis of the blade is shown as drawn through the circular enlargement l6 and the portion of the blade designated A is indicated to be shorter than the portion of the blade indicated B.

In Figs. 3 and 4 are shown somewhat conventionally the parts of a safety razor of well-known commercial type which include a cap or bladebacking member 20, generally rectangular in outline and having a concave blade-engaging surface. The cap is provided with a central longitudinal blade-locating rib 2| which is designed to fit the longitudinal slot M of the blade and thus accurately to determine the transverse position of the blade in the razor. Projecting above the rib 2|, as seen in Fig. 1, is a threaded cylindrical stem 22. This stemis flattened at 23 on both sides where it merges into the rib 2| so that this portion of the stem is not wider than the rib and does not obstruct the presentation of the blade by endwise movement, as suggested in Fig. 1. The cap is also provided with reenforcing corner lugs 24. It will be noted by reference to Fig. 2 that the reentrant corner recesses of the blade are of such size and shape as to afford ample clearance for the lugs. The lugs, therefore, do not touch the blade and have no function in locating it. The proper longitudinal position of the blade upon the cap is determined by the engagement of the end of the rib 2| with the curved edge of the transverse enlargement |5 of the blade.

Cooperating with the cap 20 is a guard member 25 having a blade-supporting face which is shouldered to permit the blade to be transversely flexed over it when the blade is clamped between the cap and guard members. The guard is provided at its outer edges with downturned guard flanges 26 and is centrally perforated to receive the threaded stem 22 of the cap. A tubular handle 21 completes the safety razor assembly, this being internally threaded at'its upper end to engage the threaded stem- 22 of the cap.

The blade herein shown may be placed directly on the inverted cap of a safety razor construction and arranged for complete detachment of the cap from the guard, since the elongated slot I l receives the blade-locating rib 2| of the cap and the central enlargement I6 receives the stem 22. The blade, however, may be also conveniently presented to a safety razor in which the cap and guard are connected to permit only limited separation to receive a blade presented endwise between them. For that purpose the razor herein shown may be provided with means, such as a stop, to prevent complete disengagement of the handle from the stem of the cap. In such razor the sides of the blade slot l4 slide upon the walls of the rib 2| and freely pass the flattened portion 23 of the stem 22. When the cap is free to be completely disengaged as suggested in Fig. 1 the flattened portion of the stem is not needed and the blade may be placed directly on the cap as already explained.

It will be noted that when fully presented in shaving position the solid end I of the blade projects outwardly beyond the end of the cap 20 and the corresponding end of the guard 25. On the other hand, the intersected end portion |2 of the blade is located within the confines of the cap and guard, being shown in Fig. 2 as flush with the end edges of these members at the left-hand end of the razor.

I have found that the user in handling openend blades of the construction heretofore available, particularly in clamping the blade, has usually contacted the open end of the blade with his thumb or finger and has partially resisted by this contact the torsion imparted to the razor head in screwing down the handle. The stress to which the blade is thus subjected tends to spring the side portions thereof or to deflect outwardly one side portion so that, when the blade-clamping operation is completed, excessive edge exposure has been created in one or more portions of the cutting edge.

That this objectionable stressing and deformation of the blade is completely obviated in using the blade of my invention will be apparent from an inspection of Fig. 4 where the head of the razor is shown as held between the thumb and finger of the users left-hand while he screws home the handle 21 with the thumb and finger of his right-hand. From this figure it will be apparent that the open end |2 of the blade is fully protected from all contact with the hands of the user, there being nothing to disturb or distort the position of the blade during the blade-clamping operation.

The blade above described has been selected as an illustrative embodiment of my invention but it will be understood that there are in the hands of users a great many safety razors having blade-locating projections of a variety of different designs and that the blade of my invention may be correspondingly apertured. The shape of the slot and its enlargements and the specific outline of the blade are, therefore, matters of secondary importance and may be varied within the scope of my invention so long as the blade is of the open-end type and the edge-of the blade bounding its open-end is not more than half the length of the blade-clamping cap member when assembled in the razor, being thereby protected from torsional stress when the user clamps the blade for shaving.

Having thus disclosed my invention and described in detail an illustrative embodiment thereof I claim as new and desire to secure by Letters Patent:

1. A flexible razor blade for use in safety razors of the type in which the blade is positioned between cap and guard members and is maintained transversely flexed thereby when the members are clamped together, said blade having a substantially rectangular body sharpened at its longitudinal edges and having transverse unsharpened edges, and being also provided with recesses located in its corner portions providing clearance spaces of suficient area to prevent clamping pressure by the corners of the cap member of the razor, said blade having a central longitudinal slot which opens out through one of said transverse edges, the latter edge being disposed at a distance from the transverse axis of the blade which is less than the distance at which the other transverse edge is located from said transverse axis.

2. A flexible razor blade for use in safety razors of the type in which the blade is positioned between cap and guard members and is maintained transversely flexed thereby when the members are clamped together, said blade having a substantially rectangular body sharpened at its longitudinal edges and having transverse unsharpened edges, and being also provided with recesses located in its corner portion providing clearance spaces of sufficient area to prevent clamping pressure by the corners of the cap member of the razor, said blade having a central longitudinal slot which opens out through one of said transverse edges, the latter edge being disposed at a distance from the transverse axis of the blade which is not more than half the length of the blade-clamping cap member when assembled therewith and being thereby protected from torsional stress when the user clamps the blade for shaving.

3. A flexible razor blade for use in safety razors of the type in which the blade is positioned between cap and guard members and is maintained transversely flexed thereby when the members are clamped together, said blade having a substantially rectangular body sharpened at its longitudinal edges and having transverse unsharpened edges, and being also provided with recesses located in its corner portions providing clearance spaces of suflicient area to prevent clamping pressure by the corners of the cap member of the razor, said blade having a central longitudinal slot which opens out through one of said transverse edges, the latter edge being disposed at a distance from the transverse axis of the blade so as to lie within the confines of the blade-clamping cap member when assembled therewith.

4. A flexible safety razor blade adapted to be clamped for shaving in a position of transverse curvature and having a substantially rectangular body sharpened in its longitudinal edges and recessed at its corners, being thereby provided with elongated end portions of reduced width bounded by transverse unsharpened edges and having a central longitudinal slot which opens out through one of said transverse edges, that part of the blade having the slotted opening in its transverse edge being substantially shorter than the part of the blade having an uninterrupted transverse edge.

5. A safety razor blade having a substantially rectangular flexible body sharpened in its longitudinal edges and recessed at its corners, being thereby provided with elongated end portions of reduced width bounded by transverse unsharpened edges and having a central longitudinal slot which opens out through one of said transverse edges, the latter edge being disposed at a distance from the transverse axis of the blade which is not more than half the length of the cap of the razor with which said blade is to cooperate, the closed end of the slot terminating in a line connecting the adjacent ends of the cutting edges.

6. A flexible razor blade adapted to be clamped for shaving in transversely flexed position between the cap and guard members of a safety razor, said blade having an elongated body sharpened throughout its longitudinal edges, bounded by unsharpened transverse edges and provided with a central longitudinal slot terminating at one end in line with the ends of said sharpened edges and at its other end intersecting one of the transverse edges of the blade, the said intersected edge being adapted to be located within the confines of the cap and guard with which the blade is to be used and thereby protected from torsional stress when the user clamps the blade for shaving.

7. A safety razor having cooperating bladeclamping members and a central stem, in combination with a flexible blade sharpened in its longitudinal edges and adapted to be clamped for shaving in a position of transverse curvature and having unsharpened end edges, the blade having also a central longitudinal slot intersecting one end edge of the blade and containing an enlargement fitting the razor stem, said blade being shorter from its stem-receiving enlargement to the edge intersected by the slot than from the enlargement to its uninterrupted edge.

8. In a safety razor having cooperating cap and guard members shaped to clamp a flexible blade between them in a position of transverse curvature; a blade having a substantially rectangular body of thin flexible steel recessed in each corner whereby it is provided with elongated end portions of reduced width bounded by unsharpened transverse edges and being sharpened throughout its longitudinal edges, the blade also having a central longitudinal slot intersecting one of said transverse edges and. terminating within the other end of the blade in line with ad acent ends of opposed sharpened edges, the blade being of such length at that end having the intersected edge as to lie within the confines of the cap and guard members, thereby being protected from torsional stress when the user clamps the blade for shaving.

LOUIS H. YOUNG. 

